500+ Towable RWHP Setup

[windrunner408]

I ended up hijacking and derailing Adrian's thread about his restructure when I mentioned that I am in search of a single turbo'd 500+hp tow tuned truck. So I am starting this thread to hopefully spur some discussion about what is all involved in making a 500hp truck that can actually tow the maximum weight capable of a ball hitch below the bumper of 12.5k.

Since I bought my truck, I have really only ever wanted a setup that could put down 500+hp and hook up to a 12.5k load and tow it anywhere. I very rarely ever actually tow but I like having the option to if I want to because i never know when I might need to help someone out and I just don't see the point in having ONLY a fast truck as I would rather have a sweet car for that over a truck but whatever on that. You get the point.

Ok so in my quest, I figured I would need some serious fuel and air to make a 500hp tow tune hence why I went with 190/100s. I had heard that 500 towable horse power could be had with 175/75s and compounds so I knew I would need a turbo that could flow A LOT of air. I had looked at alot of single non-VGT turbo setups as they would flow more air than any VGT turbos that were currently available but the down side is that the large single non-VGT turbo setups have spoolup issues so that pretty much limited me to compounds.

Well I ran into Adrian, he mentioned this Dmax Stage 2 4094va turbo that was a VGT design that was bigger than anything out there and that spoolup would probably be able to be used with towing, and from there I was hooked and decided to pursue this with him.

I was able to put down over 600hp on TSD's SPD tune written for a stock turbo but the truck was a REAL dog to drive on the road. I have tried Eric's Xtreme X, Street, and Vivian's Looney Wild. Out of all of them so far, Vivian's looney wild without any tweaks is the most responsive in comparison to the others that I have tried. Now I have worked with Eric and he has made his Xtreme X slightly more responsive than the looney wild but the EGTs are still too high. Also my fuel economy seems to have dropped about 3 mpg in comparison to the Stage 1 and Stage 2 turbos that I ran on my truck but those turbos definitely did not flow enough air to support towing 12k as EGTs would get too high way to quick.

Basically what I am seeing right now is that this turbo just isnt operating in its efficiency range. It definitely flows a lot of air but there is something that is keeping it from building boost as quickly as the stock turbo. I think this deficiency is causing the engine to run rich and burn too much fuel. Hopefully live tuning will fix this spool up issue and there will be enough air and fuel added in correctly to make this 500hp towing monster.

Ok well anyways, my thoughts on what the characteristics of a such a tow tune needs to be is that a lot of fuel needs to be able to be injected in a relatively short Pulse Width so the amount of timing is minimized to keep cylinder pressures in check and a lot of air needs to be shoved in to keep EGTs down as well. Now the fuel part is relatively easy (IMO) because large nozzle injectors can be used but then proper atomization comes into play but I think bumping up the ICP can help with this.

Well these are my thoughts. I love to get more insight on this. So jump in and let's discuss.

[colo_dually]

Subcribed, I'm always curious to see 'towable' power levels pushed.

[Brew_WY]

I am interested as well, as I want to eventually attain a slightly lower number (450ish HP at the wheels and tow). I see it is on your list of to do's, but I would be interested in how a set of performance exhaust manifolds like Steed Speed or others(don't know of them) would help with your spooling issue. Subscribed.

Cheers,

Brew

[mudrunninpig]

watching this one also

[colo_dually]

I think another aspect of this that has to be discussed is how much weight are we talking about towing with that 500HP, Nate?

[Brew_WY]

Originally Posted by colo_dually

I think another aspect of this that has to be discussed is how much weight are we talking about towing with that 500HP, Nate?

I believe Nate had stated that he wants to be able to tow at least the rated 12.5K LBS that it is rated for at the receiver hitch with weight distribution. I personally am looking at wanting to tow around 10K LBS, but this kind of power will be quite a few months down the road.

[Tuscany]

I don't know much about a towing setup but it seems to me that if you want to attain a certain horse power rating with lower egt's and be able to use the truck for what it was designed for IMO you could throw all the fuel and air at it you want but your gonna keep hitting a wall with the high egt's. It seems only logical to me that this could be accomplished by opening up your intake and letting it flow better, getting bigger CAC piping a bigger intercooler, etc. Anything that would allow you to flow the most possible air into the cylinders.

My reasoning goes hand in hand with Adrian's thoughts when he first started developing these turbos. More air with the stock amount of fuel is producing bigger numbers than anyone imagined. I think if you could take your 190/100's and maybe drop to a 190/50 or even a 175/75 you could produce the numbers you need all while being able to pull big grades and keep your egt's low.

In this scenario air is your ally it is your friend, the more air you can bring into the combustion chamber the better it will allow you to keep the egt's down under major loads. Now I don't have any concrete evidence as I didn't write down for proof of temps but I have a fully functioning ram air induction hood that forces all the air directly to the cold air intake. When I had my hood off of the truck doing the oil cooler replacement and egr delete I took it for a drive when it was done and the egt's (hood off test drive) got around 50-150* hotter than when I had ran it previously with the hood on before the repairs. Just food for thought but its my $0.02

[1fastTRX]

Other than egt's... what prevents us from towing in a race tune currently? For instance IDP Xtreme Street, TSD SPD, or Quick Tricks Looney Wild. If a stage 1 or 2 turbo were used along with modded intake manifold and modded headers and egts could be sustained under 1200... is that enough? Or do other parameters in the tune need to be modified as well? Is tranny slippage a concern at that point?

[drunk on diesel]

aggressive timing makes power and lower EGT, but puts more heat in the piston crowns

[windrunner408]

Originally Posted by drunk on diesel

aggressive timing makes power and lower EGT, but puts more heat in the piston crowns

I think this right here is what makes towing on a race tune unadvisable. I know that there is more to it than just EGTs. I think cylinder pressures have to be able to remain in check as well.

Thanks guys for the responses.

I'm with you Tuscany on definitely needing more air than fuel but as I mentioned, I think it will still take a certain amount of fuel to make 500hp and the more fuel you can deliver at the right moment (i.e. with hardly any increase in timing) in the power stroke, the more power that I believe will be available to you (provided sufficient air is provided as well).

So with that being said, I also would think that a ported intake manifold and performance exhaust manifolds would help this turbo spool better and that may very well be what is needed. I dont know. I know with the non-VGT guys the manifolds like the steed speeds, out law headers, MPD manifolds, and black widow manifolds are helping with spool up and turbo response so I it only stands to reason that they would help with this turbo as well. I would just like to see if I can get it to run right first with the stock manifolds (intake and exhaust) and optimal tuning and then I will step it up. I know I would get these parts anyways if I was doing compounds so it isnt like I have anything against them.

I also know Adrian mentioned his Stage 4 (use to be Stage 5) should spool quicker than the Stage 3 and I have reason to believe that he is right. Like him, I too have went behind enemy lines and did some reading on the Dmax Stage 2 (aka: MTW Stage 3) turbo and the Danville 72mm VGT turbo I know has been used for towing so maybe that will have to be what I end up with. I dont know.